Pressure-gage.



E. www PRESSURE GMM?. APPLICATION FILED @UBB 2, 1013. pmg@ Patented Dec.29, 1914 2 SHEETS-SHEET l.

im a einen "i .agian Specification el Lettere Patent.

inca-i ce.

.application nieu June ft, i913. Serial Nc. Wiw.

To aZZ whom i may concern.'

Be it known that l, ERVIN G. Bannay, a citizen of the United States,residing in Newton Highlands, dlesex and State of lllassaobusetts, havein vented an improvement in Pressureages, of which the followingdescription, .in con nection with the accompanying drawings, is aspecification, like letters on the drawings representing like parts.

.The present invention relates to a pressure gage, and is embodied in aninstrument of that class by means ot' which Variations in pressures orpressure differences are indiF cated or recorded by a movable indicatingmember in conjunction with a scale or chart.

The purpose ol' the invention is to arrange the instrument in sucb a waytba-t it 'will operate accurately in cases Where yery light pressuresare encountered, the arrangement being sucb that friction is almostentirely eliminated, While the parts are always naintaincd in stableequilibrium without the-use of guides or analogous devices, 'which causeinaccuracies due to friction.

A further feature of the invention consists in an arrangement whereby'the reading of the instrument be caused to vary as some function of tbepressures or pressure difference, instead of varying as the simple ratiothereof, and also whereby the reading' can, by a suitable adjustment, bemagnified as desired for any given pressures or pressure dierences.

In accordance with the invention, tlxepressures undici-observation areexerted on opposite sides of a sealed bell ior bells shown as connectedwith an oscillating beam, and l the force due to pressure acting on thebells is measurablv counteracted a. displacingmember also movableWithftbe beamfand bell and extending into a liquid, the change inbuoyancy ofthe said displacing member, as the beam is moved ,by tbebell, finally bringing tlie @several forces acting on the beam to astate of equilibrium, and determining the position' of the indicatingmember which shows the reading desired.

In making and using the instrument, I prefer to use mercury as theliquid and to make the displacing member of iron or, steel;

and in this case it is necessary to vadd a Weight to the displacingmember and outside o'f the mercury or buoyant liquid 'in order to keepthe displacing member'. submerged beyondits ncrmal'floating depth.

in the county cEMlid This Weight is c nested to and so proportioned withrel non to the displacing member as to cause tlie center et ,gravity ofthe displacing member connected. parts to be so positioned to the shapeof tbe displacing merel; and 'to tlie center ci buoyancy or si n' reef,tliat stable equilibrium l ce 'will exist; and the fik, ssociated parte,therefore, will bave no tendency te tip from their normal verticalposition, as til y rise cr fall. il have also slicwn tlie instrument so'arranged and tbe pressures applied to tie instrument in sucb. a 'Waythat tbe pi; pculerating pressure tends to tbe' lacing member out fromtlie liquid, uit being that the parts always remain in stableequilibrium, se that no guides or equivalent devices are required tclicl tlie displacing; Amemberyin its operative pssiti n, v Figure l is"Ve 'cal section, partlyiin elevation, of an instrument embodying theinvention, '4.9. is a. similar vieu/'showing a moei. cation tieren?lleierring te Fi the ing ieli l is 1 l bcr 2, and is conne .l Yam orlever vnf consisting,v ci' suitable pressuic-iA side of the casir anindicating,l zum 5 i pen adapted 'to travel over the surface cfarotatable chart G. The bell l extends into an annular receptacle 7 whichis admet-ed to contain a .liquid sealing tlie inoutli olf the bell; andpressure is admitted c tbe i rior et the bell above tbe sealing liuuiInrougn the inlet 8 which extends tinker,J the bottom of the receptaclei" to the Within the inner Wall thereof. under observation admitted tothe cliamber 2 through a pipe 9,]sc that any .change in tbe diierencebetween tbe pressures tends to cause a movement oi? tbe bell i, in onedirectien' or tbe other and a consequent movement of the arm l andindicatore. In using the instrument, tellen constructed as herein shown,'the prepouderating pressure is exerted on the interior' ci tlie'bell,so that the tendency of the bell is itc motie upward as the pressureci'erence increases. For the purpose of bring-ing about a state ofequilibrium when tlie indicator 5 is-in such position as to indicatedesired terms'or receivcillating i s e pivot bearing l ling through tlieoutfunctions the difference'ici pressure, a dis?l The other pressurelreceptacle 12 which is concentri j receptacle?v which contains thesealing liquid for the bell.

with the displacing member 10 Vso as to lplacing member 10 is employed,the said displacing member beingmovable with beam 3 and extending into aliquid,l so that the buoyant -eect of the liquid on the dis! placingmember changes as the beam moves,

and', finally restores equilibrium.'

In the construction shown inY Fig. 1, the displacing member 10 islocated insideof 'the bell 1, and the liquid in which saiddisplacing-member extends is cont fined in-a with4 the The' jweight 11is connected cause' the proper submersion of said d isplacingy memberfor the zeroV position," and is so located that the center of gravity'ofthe displacing member andits attached parts is lciv with respect to thecenter of buoyancy or supportv so that all'the moving parts remain instable equilibrium of iotation-at alltimes. The receptacle12 is shownas4 mounted on ribsll at the bottomy of the 'chamber'7, so aste adord'aspace for the iuid pressure entering through the inlet 8 to communicatewith the interior of the bell I1. In. the construction shown, theinstrument is adapted to show a reading which varies as some functionof. the pressure difference, such as the, functional relatlon bej,

tW'een velocity head and rate of flow. of fluids, and thisl isaccomplished by shaping the displacing member 1,0, so that itshoriaontal crosssectional area progressively varies, thereby modifyingthe change in buoyancy due to the movement of the displacing memberWitlirelation to the liquid. 'It is obvious, however, that iftheinstrument -is to indicate a reading that varies in direct lratio to thepressure difference, the displacing `,member can be made of uniformcross-sectional area throughouas indicated in dotted lines, Fig. 2. 4

The instrument illustrated in Fig. 2 is especially designed for usewhere very slight pressures are encountered, and in thisinl strument Iemploy two sealed bells 14 and 15 suspended from a beam 1G which carries.the indicator 17, .the said beam being pivoted at 18, While the bellsare pivotally supportedv at opposite sides ofthe. said pivot.

In this case the preponderating pressure. is

admitted through a pipe 19 to the interior ofthe belll, the same jjrcssurebeing conveyed through a pipe 20 to the outsideof the bell 14, sothat 'the combined areal of Y. bell 15.

sealed in liquid contained inra main receplthe two bells yisI subjectedto pressure.' Similarly the lesser pressure is admitted" through thepipe-21 and branch 22 to thel inside of the bell 14, and the outside ofthe Both of the bells are shown as tacle or chamber, the pressure at theoutside of the bells being confined by hoods 23 and 2e?,I which aresealedin the liquid, but open .below the surface of the liquid`to'receive A the yokes 25 which support the bells. In

this case, the displacing member 26 is susvWhen the liquid contained inthe receptacle 2 8 is of greater density than the den, sity of the.displacing member 2b, an addi,-

tional. Weight, such as the Weight31, maybe employed to cause the'desire'dvsubmersion of lthe displacing member. This Weight is shown assupported below the reservoir28, being connected tothe displacing memberby -ayoke, so that `the center of-gravity of' the displacing member andthe parts connected` therewith are suiiicientlydow with relation to thecenter of buoyancy or support, to `maintaina state of stable/equilibriumthroughout the range of, operation. The lfunction of the Weight 8l isthe same as that of the weight 11 previously described;` but in theinstrument shown in Fig. 2, this Weight may be dispensed with if theliquid usedis of. less density than that of the displacing member. Aperfect balance of the parts is .brought about by means of an adjustableWeight 32 at the opposite side ofv the pivot 18 so that the pointer 17will stand at the 'zero mark on the scale when no pressures are appliedto theinstrument. It is obviousin this construction that .the motion dueto the force exerted by the pressures is transmitted through a niomentarm to the vindicator, so thatby adjusting the said moment arm to varythe moments of force required to bring about a state of` requilibrium,the' movement of the indicator along the scale' can be varied-per unitof pressure difference, so that the instrument canA be adjusted forvarious conditions Without changing the sizes of the bells or.displacing member or the graduations of the scale With relation to thepointer. `'In-this instrument, this adjustment. can conven- -iently be'made by moving the displacing member 26and4 its liquid receptacle 28with relation to the pivot 18, and correspond- Aingly adjusting themovable weight 32 to bring about a perfect balance of the partsA Whenthe pointer is at zero.

What I claimv is: j 1, In a-pressure gage, the combination with a bellsealed in a liquid and subjected to opposed'pressures outside andinside; of

ile"

izo

an @mumble 'beam to which said beu is f connected; al displacing memberalso con-V nected with said beam, and extending into a li uid; and meansfor adjusting the length liquid, of an indicator; means for coimecb of te moment arm through which the presing saidindicator with said bell; adisplacsures act to cause the movement of the'disl mg member connectedwith said indicator placing member. Y and extending into a li uid; and aweight n a pressure gJage the combination associated with said dispacing member and with a pressure recelving-bell sealed in a so locatedwith relation thereto that ythe liquid; of an oscillatable beam toWhichsaid center of gravity of the displacing member bell is connected;a displacing member conand weight is always below the center of necteclwith said beam and extending into buoyancy or support of the displacingmema liquid of greater density than that of the ber. displacing member;and a Weight connected In testimony whereof, I have signed my with saiddisplacing member and being outname to this specification in thepresence of side of the liquid, the center of gravity of two subscribingwitnesses.`

said weight being below the-center of grav ERVIN Gr. BAILEY. ity of saiddisplacing member. Witnesses:

3 In a pressure gage, the combination JAS. J. MALONEY,

withA a pressure receiving bell sealed in. a i Y -M. E. COVENL

